Heat-exchange apparatus



June 1929- R. VUILLEUMIER HEAT EXCHANGE APPARATUS Original Filed Oct.14, 1916 2 Sheets-Sheet FIG M V awuewfoz 351 flflozwug;

I- J M June 4, 1929. R. VUILLEUMIER 1,716,333

HEAT EXCHANGE APPARATUS Original Filed Oct. 14, 1916 2 Sheets-Sheet 2FIGS. FIG. 7.

Patented June 4, 1929.

UNITED STATES PATENT OFFICE.

RUDOLPH VUILLEUMIER, OF NEW ROCHELLE, NEW YORK, ASSIGNOR TO THE SAFETYCAR HEATING & LIGHTING COMPANY, A. CORPORATION OF NEW JERSEY.

HEAT-EXCHAN GE APPARATUS.

Application filed October 14, 1916, Serial No. 125,534. Renewed December6, 1920. Serial No. 428,816.

This invention relates to the transfer of heat, and with regard tocertain more specific features, to an apparatus for low temperaturework.

One of the objects of the present invention is to provide simple anddurable apparatus for effecting a rapid transfer of heat between twofluids.

' Another object is toprovide an apparatus of high thermal efiiciencyfor conducting heat from one fluid to another without sacrifice ofmechanical strength or economy of construction.

Another object is to provide a compact and reliable heat interchanger oreconomizer capable of effective operation with but a slight differencein temperature between the warm er and the colder fluids, and operatingat minimum external heat losses.

Other objects are to provide apparatus of the above general type inwhich the temperature gradient across the paths of the fluids isminimized, and the temperature gradient along the paths of the fluids ismaintained at a maximum.

Other objects will be in part obvious and in part pointed outhereinafter.

The invention accordingly comprises the features of construction andoperation, combinations of elements, and arrangements of parts which areexemplified in the structure hereinafter described and the scope of theapplication of which will be indicated in the following claim.

In the accompanying drawings, in which are shown one or more of variouspossible embodiments of this invention,

Figure 1 is an elevation, partly in section, of acounter-current'recuperator.

Figure 2 is a transverse section on the line 22 of Figure 1.

Figure 3 is a View similar to Figure 1, of a multiple-path construction,in which one of the fluids is caused to pass through a plurality ofconduits within the container for the second fluid.

Figure 4 is a transverse section on the line 4-1 of Figure 3.

Figure 5 illustrates a modified construction comprising concentric coilsfor'one of the fluids, with no heat-conducting solid particles withinthe conduits for said fluid formed by said coils.

Figure 6 is a transverse section on the line 66 of Figure 5.

Figure 7 is an elevation partly in section, of a cross-currentrecuperator utilizing a coil for one fluid wound within an annularconduit for the second fluid, with heat-conducting beads in contact withthe second fluid on y.

Figure 8 is a transverse section on the line 8-8 of Figure 7.

Similar reference characters refer to similar parts throughout theseveral figures of the drawings.

In considering the present invention with relation to the prior art, itmay be noted that for many years attempts have been made to transferheat effectively from one fluid to another, as in high andlow-temperature work. The apparatus used for this purpose has ordinarilybeen of one or two types: first, the sothermal contact; in this type ofappar'atus,.

the'heat is transferred continually through the walls separating thefluids. In both the regenerator and rccupcrator types it is preferable,but not essential, that the fluids flow in opposite directions, or atleast notin the same direction, and this opposite flow is known'as thecounter-current system. The rapid transfer of heat from one fluid toanother fluid of almost the same temperature, together with economy ofconstruction, mechanical strength to withstand the high and lowpressures utilized, and the prevention of frost or other prejudicialphenomena in the case of low-temperature work, are desiderata notadequately attained in apparatus and processes now known in the art. Asthe description proceeds, it will be seen that these and otheradvantages are realized in the present invention.

Referring now to the accompanying draw- I tube for a fluid A. 1Surrounding this conduit is a second conduit or container 2 providedwith suitable heat insulation or packing 3 to protect it from theatmosphere, and so arranged that a second fluid B may pass through thespace between the inner wall of the outer conduit 2 and the outer wallof the mner conduit 1, preferably in a direction opposite to the flow ofthe fluid A, as indicated by the arrows B, A, respectively, in Figure 1.i

The wall of the inner conduit 1 is of such material and thickness thatit has a fairly high thermal conductivity, so that heat imarted to thiswall from one of the fluids will be transmitted through the wall, whereit may be absorbed by the other fluid.

In order to increase the transfer of heat from one fluid to the other,without involving the use of an expensive or mechanically weak wall 1,the channels through which one or both of the fluids may be passed arepreferably filled with solid matter of comparatively high thermalconductivity, such as copper beads. In Figures 1 and 2, both channels aand b are filled with copper heads 5;

. in other embodiments of the invention, de-

scribed hereinafter, these heat-conducting particles are utilized onlyin the channels for one of the fluids. Copper having a thermalconductivity several thousand times the conductivity of still air, andfar in'excess of the average conductivity of fluids, the heat travelsbetween the fluids and the wall 1 much faster than it would if the beadswere not present, notwithstanding the tortuous path of the heat from onebead to another and the slight thermal resistance encountered by theheat in passing from one bead to another and between the wall 1 and theadjacent bead. And this acceeleration or intensification of the heattransfer makes possible the use of a less eflicient and consequentlystronger and less expensive wall '1 for a given efliciency of theapparatus.

In operation, the beads 5 offer some resistance to the flow of the fluidthrough the channels a, b, but this canbe reduced to a negligiblequantity by suitably proportioning the beads themselves: that is, thelarger the beads, the larger the interstices available for the passageof the fluid, and the lower the resistance offered-to the fluid.Thebeads serve-to break up the fluid into a large number of finestreams, so that all the parts of the fluid are brought into intimatethermal contact with a series of these particles of low thermalresistance, with the-result that the transfer of heat between the fluidand the particles or beads and through the beads to or from the dividingwall 1 and the other fluid, is materially accelerated or intensified, sothat an effective heat transfer may be main tained even though thefluids A and B pass through thev apparatus at a comparatively highvelocity; and the temperature gradient across the path of each fluid ismaintained at a minimum, owing to the rapid equalization, through themetal beads, of any unbalanced heat distribution that might tend tooccur. This, of course, increases the efiiciency of the apparatus byuniformly taking from or imparting to each portion of the fluid the samequantity of heat, without involving the use of unduly small conduits forthe fluid.

While maintaining a rapid heat transfer across the path of the fluid,and equalizing the temperature of the various portions ofthe fluid at agiven plane taken transversely to the axis or direction of flow of thefluid, as above described, it is likewise a feature of the presentinvention to prevent or minimize the transfer of heat along the path offlow of the fluid, that is, lengthwise or axially of the conduit. Thisis for the purpose of reventing the fluid portions that have attained adesired temperature, from losing that temperature by a conduction ofheat between said portion and a portion which has not yet attained thattemperature. For example, in the refrigeration of air, the air as itleaves a given stage of the apparatus is colder than the air enteringthe same stage of the apparatus, and any transfer of heat from theentering air to the air leaving the stage would raise the temperature ofthe latter and thus tend to reduce the efliciency of the apparatus, asby requiring the use of a greater number of stages to effect a giventemperature drop in the air. In the resent invention, any heat transferalong tie path of the fluid is reduced to a negligible amount by theprovision of layers of heat-insulating particles 7 at suitable intervalsalong the axis of the containers. These particles or beads are of a lowthermal conductivity, and the spaces between the particles aresufliciently large to permit the passage of the fluid therethrough without undue resistance. These heat-insulating beads neither aid nor hindermaterially the transfer of heat to the walls of the conduit through thebeads 5 of high thermal conductivity, since said transfer is effected atapproximately right angles to the flow of the fluid. The insulatingparticles serve merely to greatly lessen or minimize the passage of heatenergy axially of the container.

. In Figures 3 and 4, there is illustrated a modified construction inwhich the fluid A passes in one direction through a plurality ofconduits 9 arranged within the container 2 in such manner that the fluidB may pass in the spaces between the inner wall of the container 2 andthe outer'walls of the conduits 9. The channels through which the fluidsflow are filled with heat-conducting beads 5, separated at intervals bylayers of heat-insulating particles 7, as in Figures 1 and 2, and theoperation of this embodiment of the invention otherwise correspondsgenerally to the above description of the operation of the ap paratusshown in Figures 1 and 2. By subdividing the fluid A in Figures 3 and 4,there is provided a greater conducting surface in the dividing wallsbetween the two fluids, thereby permitting a more compactstructurc,

with attendant reduction of external radiafurther modification, ofadvantage particularly in connection with gases at comparatively highpressure. Here the fluid A is caused to pass through the series ofconcentric coils 11, 12, 13 in a generally downward direction, while thefluid B, as before, flows upwardly in the spaces between the inner Wallsof the outer container 2 and the outer walls of the coils 11, 12, 13. Byhaving the fluid A pass through coils instead of along a path parallelto the path of the fluid B, as in Figures 1, 2, 3 and 4, the fluid Atravels a greater distance along its container for a given distance oftravel axially of the flow of the fluid B. That is, in the precedingembodiments of theinvention, the fluid A in flowing one foot through itsown container, would advance one foot along the path of travel of thefluid B, while in the apparatus shown in Figures 5 and 6, the fluid Amust flow a number of feet through its coils 11, 12 or 13, as the casemay be, in order to advance one foot axially of the outer container 2.This permits a comparatively high velocity for the fluid through itscoils for a given velocity axially of the outer container, and thehigher velocity along the coils results in increased friction oreddy-currents, which tend to break up the fluid and bring all portionsof it into frequent contact with the walls of the coils and thusincrease the conduction of heat, with out the use of metal beads.

In this embodiment of the invention, the second fluid B flows at a lowerpressure and at a lower velocity, so that the metal beads are providedto increase the heat conduction between this fluid B and the walls ofthe coils 11, 12, 13. The larger cross-section, lower pressure andreduced agitation due to lower velocity of the fluid B would all tend tohinder the rapid transfer of heat unless the solid particles wereutilized, and conversely, the use of the solid particles does not havethe resisting effect on the fluid fiow'that would occur if the fluid Bwere operated at higher velocity through a smaller cross-section.

In using this apparatus ofFigures 5 and 6 for obtaining lowtemperatures, an advantags is found in that the comparatively highvelocity of the fluid A through the coil-i 11,

12, 13, reduces or prevents stoppages of the apparatus due to particlesof frost, such as water vapor, carbonic acid, or other impuri-' ties,which an intensely cooled gas usually carries, and which at a slow fluidvelocity tend to adhere to the walls of the coils. The fluid B isassumed to be substantially free from the impurities which wouldoccasion the formation of frost, and hence this latter fluid may beoperated at a lower velocity.

A further modification is illustrated in Figures 7 and 8 of thedrawings, where the two fluids A and B are caused to flow cross- Wise ofone another in what may be termed a cross-current apparatus. In thisembodiment of the invention the fluid A passes through coils 15 arrangedin the form of a cylinder of large diameter compared with the diameterof the pipe or tube of which the coil is formed. This cylinder is placedwithin a conduit 16 of annular cross-section, comprising the inner wall18 and the outer Wall l9.- Owing tothe ratio of diameters of cylindertube, the fluid A travels through the apparatus in an approximatelyhorizontal direction, and thus encounters at substantially right anglesthe vertically traveling fluid B. If this type of apparatus is used forlowtemperature work, the space within the inner wall 18 may be used tohouse the container of a low-temperature liquefied gas or apparatus forthe separation of its constituents, since this inner space iseffectively protected from the temperature of outside air by the annularconduit 16, and the fluid undergoing heat exchange therein, it beingnoted that the outer cylindrical wall 19 may be insulated as is shown inFig. 1.

v In the above description,it is to be understood that the apparatus andmethod of the present invention-may be utilized in a variety of ways, asin high or low-temperature work,-

and in fact in many if not all of the situations Where an effectivetransfer of heat is desir able.

In view of the above, it is believed that the various features of thisinvention will be above set forth, it is to be understood that.

all matter herein set forth or shown in the accompanying drawings is tobe interpreted as illustrative and not in a limiting sense.

Having thus revealed my invention, 1

other advantageous claim and desire to secure by Letters Patent of theUnited States:

In apparatus of the class described, in combination, a plurality ofcoils for a fluid, ar-

ranged concentrically with respect to each other, a containersurrounding the coils and means for insulating from one another thearranged for the passage of a second fluid beads at points along thepath of said second 10 between the inner wall of the container andfluid, to reduce the transfer of heat along the the outer walls of thecoils, beads or particles path of said second fluid.

5 of high thermal conductivity arranged to In testimony whereof, I havesigned my contact intimately with said second fluid, to name to thisspecification this 13th day of facilitate the transfer of heat betweensaid October, 1916. coils and all portions of said second fluid, andRUDOLPH VUILLEUMIER.

